Storage subsystems provide system mass storage incorporating many storage devices. Storage devices usually include hard disk drives, but may include solid-state drives, optical drives, or tape drives. Storage subsystems include within a single storage chassis one or more storage devices, power supplies, and possibly one or more storage controllers, including Redundant Array of inexpensive disks (RAID) controllers.
In order to provide non-stop operation, redundant controllers, power supplies, and/or storage devices are often provided in the storage subsystem. Additionally, such assemblies are generally provided as field replaceable modules or FRUs. Field replaceable modules are packaged individually, in order to facilitate removal and replacement of individual controllers, power supplies, or storage devices. Additionally, such modules are often hot replaceable, and able to be replaced while the storage subsystem is powered up and even actively conducting I/O operations to one or more storage devices. Individual storage devices are commonly packaged within a storage device module consisting of a sheet metal tray for mounting the storage device and a front bezel incorporating a latching mechanism, and in some cases visual indicators.
Many storage devices incorporate relatively large and robust midplane connectors, which convey power and I/O signals between the storage device and the midplane. Such connectors often have high pin counts, resulting in high insertion and removal forces. In order to overcome high removal forces, storage device modules incorporate cams, levers, or other mechanically advantaged latch mechanisms.